Myothermic apparatus

Abstract

Improvements in myothermic apparatus have made it possible to measure with relative accuracy, in the sartorius of the frog or any similar muscle, not only the heat suddenly produced by a single stimulus, but that liberated over long intervals at rest, or in recovery, or as the result of prolonged discontinuous stimulation. The essential factors are a moving coil galvanometer of high sensitivity and short period; a method of measuring total heat from the area of the deflection-time curve; a thermostat in which the temp. is maintained constant within 0.001[degree]C. for long periods; and an "all-metal" thermoplle, which responds quickly, settles down rapldly, and. is very completely insulated. Other details described include an improved method of calibration; preparation and use of the gases employed (N2, O2, and CO2); and the advantage resulting from a Ringer''s solution containing phosphate (7-15 mgm. % P).